Wiper and Washer Systems: Description and Operation

WIPER/WASHER SYSTEM DESCRIPTION AND OPERATION

WINDSHIELD WIPER/WASHER SYSTEM COMPONENTS
The windshield wiper/washer system consists of the following components:
- Windshield wiper/washer switch
- Windshield wiper motor module
- Windshield washer pump
- Windshield washer relay
- W/S WIPER 25A fuse
- W/S WASH 15A fuse

WIPER/WASHER SYSTEM OPERATION
The windshield wiper motor module controls the windshield wiper motor and washer pump operation. The windshield wiper motor is a 2 speed motor and is operated at low speed in all modes except HIGH. The accessory voltage supply circuit to the windshield wiper motor provides the power for operating the wiper motor module. The windshield wiper switch supply voltage circuit is a 12-volt reference from the wiper motor module to the wiper/washer switch. The WASH, MIST, LOW, and DELAY modes are controlled by the windshield wiper/washer switch through a series of internal resistors, and the switch position determines the point on the resistor assembly where the reference voltage is applied. The windshield wiper switch signal circuit supplies the signal voltage from the switch assembly to the wiper motor module which determines the operating mode. Windshield wiper motor high speed operation is controlled by the windshield wiper/washer switch through the windshield wiper switch high signal circuit. The windshield wiper switch high signal circuit is supplied 12 volts by the wiper motor module and when the wiper/washer switch is turned to the HIGH position the windshield wiper switch high signal circuit is grounded. The windshield washer pump is controlled by the wiper motor module through the windshield washer relay. The windshield washer relay coil and switch is supplied battery positive voltage, and during WASH mode the wiper motor module grounds the washer relay control circuit energizing the relay. While the relay coil is energized battery positive voltage to the switch side of the relay is supplied to the washer pump control circuit.

CHECK WASHER FLUID MESSAGE
The Check Washer Fluid message is controlled by the instrument panel cluster using an input from the washer fluid level switch. The washer fluid level signal circuit is supplied ignition voltage through a resistor then monitored within the instrument cluster. The washer fluid level switch is normally open so the instrument cluster detects ignition voltage on the washer fluid level signal circuit whenever the washer fluid level is not low. When the washer fluid reaches the point where the driver should be informed that the washer fluid is low, the washer fluid level switch closes. When the washer fluid level switch is closed the washer fluid level signal circuit voltage is pulled low, and the instrument panel displays the Check Washer Fluid message on the driver information center. In order to prevent the Check Washer Fluid message from being displayed while sloshing is occurring in the washer fluid container, the instrument cluster is programed with a 1 minute delay before changing states of the Check Washer Fluid message during an ignition cycle.